Yes, a Grappled creature can still attack, take actions/reactions, and still threatens space.
If you want to better control a creature you have Grappled you can follow up by shoving them Prone with your next attack. They still can attack and make opportunity attacks but now they do so with Disadvantage.
It actually does not say anything about the reaction even in the basic rules in the player handbook.
A grappled creature's speed becomes 0, and it can't benefit from any bonus to its speed.
The condition ends if the grappler is incapacitated (see the condition).
The condition also ends if an effect removes the grappled creature from the reach of the grappler or grappling effect, such as when a creature is hurled away by the thunder-wave spell.
Ultimately, the DM allowed it as we could not find an actually ruling on it other than an older version of the game, which says no. I opened this Form as to debate to see if it should be allowed and or not and if so, should it be at disadvantage. Would highly suggest googling images of grappling and understand why this is a good debate topic. Thank you for your reply.
Conditions that limit your actions explicitly tell you that they do, like the Incapacitated condition.
Previous editions of D&D have had much more complicated grappling mechanics. In 5e however the Grappled condition just means the grappler is using a hand to prevent a creature from moving more than 5 feet from their current position. Narratively this can be as simple as holding onto someones wrist.
If you are interested in mechanics more akin to wrestling then I would suggest looking at the Grappler feat. Maybe you and your DM could use it as a starting point for homebrewing your own grappling system.
Would highly suggest googling images of grappling and understand why this is a good debate topic. Thank you for your reply.
Unfortunately the designer made a poor choice in naming the action (grappling) and condition (grappled) and thus it doesn't work in the way that you seem to be expecting. What you are looking for is the restrained condition instead which can happen through use of the Grappler feat as Fangeye mentioned.
It actually does not say anything about the reaction even in the basic rules in the player handbook.
A grappled creature's speed becomes 0, and it can't benefit from any bonus to its speed.
The condition ends if the grappler is incapacitated (see the condition).
The condition also ends if an effect removes the grappled creature from the reach of the grappler or grappling effect, such as when a creature is hurled away by the thunder-wave spell.
When it comes to things like this, the rules do what they say they do and nothing more. All grappling does to you is reduce your speed to zero. It is entirely intentional that it doesn't mention any other effects because there are no other effects.
It's not a bear hug, it's a firm grip on your wrist/leg/belt. All you need is one free hand to do it, and it doesn't restrict the grappler's actions either aside from taking up that hand.
Should a creature be able to make an opportunity attack while grappled?
Yes, a Grappled creature can still attack, take actions/reactions, and still threatens space.
If you want to better control a creature you have Grappled you can follow up by shoving them Prone with your next attack. They still can attack and make opportunity attacks but now they do so with Disadvantage.
It actually does not say anything about the reaction even in the basic rules in the player handbook.
Ultimately, the DM allowed it as we could not find an actually ruling on it other than an older version of the game, which says no. I opened this Form as to debate to see if it should be allowed and or not and if so, should it be at disadvantage. Would highly suggest googling images of grappling and understand why this is a good debate topic. Thank you for your reply.
Conditions that limit your actions explicitly tell you that they do, like the Incapacitated condition.
Previous editions of D&D have had much more complicated grappling mechanics. In 5e however the Grappled condition just means the grappler is using a hand to prevent a creature from moving more than 5 feet from their current position. Narratively this can be as simple as holding onto someones wrist.
If you are interested in mechanics more akin to wrestling then I would suggest looking at the Grappler feat. Maybe you and your DM could use it as a starting point for homebrewing your own grappling system.
Unfortunately the designer made a poor choice in naming the action (grappling) and condition (grappled) and thus it doesn't work in the way that you seem to be expecting. What you are looking for is the restrained condition instead which can happen through use of the Grappler feat as Fangeye mentioned.
Being grappled or restrained doesn't prevent attacking or taking action/reaction.
When it comes to things like this, the rules do what they say they do and nothing more. All grappling does to you is reduce your speed to zero. It is entirely intentional that it doesn't mention any other effects because there are no other effects.
It's not a bear hug, it's a firm grip on your wrist/leg/belt. All you need is one free hand to do it, and it doesn't restrict the grappler's actions either aside from taking up that hand.
My homebrew subclasses (full list here)
(Artificer) Swordmage | Glasswright | (Barbarian) Path of the Savage Embrace
(Bard) College of Dance | (Fighter) Warlord | Cannoneer
(Monk) Way of the Elements | (Ranger) Blade Dancer
(Rogue) DaggerMaster | Inquisitor | (Sorcerer) Riftwalker | Spellfist
(Warlock) The Swarm